Tag Archives: QRP

Building the EA3GCY DB4020 Dual-band 40 and 20M QRP SSB Transceiver Kit

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post:


Building EA3GCY’s DB4020 QRP Transceiver kit

by Frank Lagaet (ON6UU)

In May, I discovered via a newsletter that a new kit was available from Javier EA3GCY in Spain.  I was immediately sold as this was a kit from my favourite kit producer and it has 2 bands–it will also be able to do CW and there also will be a CW filter.

After building 2 MFT’s from Javier which work without problems, I needed to have the DB4020.  The MFT’s are for 20 and 40 mtrs and do DSB (double side band).  I did put them in a not-so-graceful box but they do what they are intended for which is QRP phone (SSB).   They came together without problems so I expected the same for the DB4020–I knew for sure when I saw the board:  all through-hole components (except for some capacitors which are factory soldered) and a lot of space on the board.   The board has been silk-screened with clear indications on where all components have to come and the manual has very clear instructions where each component has to be soldered with referral to a quadrant.  The manual provides a 252 quadrant page so it is a piece of cake to find where each piece goes.

What do you get?

Javier provides you with all components which need to be installed on the board and, of course, the kit board.  The components come in small marked plastic bags and all is well-wrapped up in bubble wrap.  The board is wrapped separately and that is put together with the component wrap which is then again wrapped up in bubble plastic.  All goes into an envelope.  Very well packed I must say.

Here’s a picture of the bags with components:

The silk-screened board:

I started with the resistors since that’s the easiest way. After that, I did the capacitors.  I like to solder in all flat components first, so next were the diodes and IC sockets followed by the elco’s.  The transistors were next together with all relays.  As you solder in the transistors one also has to mount the cooling heatsinks,  these cooling sinks are high and are ideal to protect the coils one has to make,  they also protect the polystyrene caps (which I always find vulnerable) when the board is upside down.

Many kit builders are afraid of winding the toroids in kits–don’t be!  It is easy.  Just take your time and follow the instructions given by Javier in the construction manual.  In this kit the builder has to wind 8 toroids:  6 are a single wire which goes through the toroid body,  1 is a toroid with 2 different windings, and 1 has a twisted pair which goes through the final toroid.  Be sure to measure the wire you need per toroid as instructed in the manual.  Javier gives some spare, so you can be sure.  You will also see that on next picture where the legs of the toroids have not been trimmed yet.  Once done I still had some centimetres of wire leftover.

Picture of the toroids ready to be soldered in:

Finally all other parts and pin headers went in,  jumpers were immediately put on where needed.

As I’m using a military-grade plastic box, I have to break-out some components like the display,  tuning encoder,  volume and rx control from the board.  I also have put an on/off switch on the box and already have the CW KEY connector ready installed. I also installed a loudspeaker in the box.  The SI5351 board and the Ardiuno Nano are the final components which go into the board after installing all wires.

Picture of the board:

I intend to attach a CW paddle to the box made out of a relay.  A HWEF tuner (from EA3GCY) which I was planning to incorporate in the box is I think a bit overkill. That HWEF tuner is already in a nice little box and would be a pity to dismantle,  also I’m running out of space in the box…  Maybe I can fit in a 9-1unun which would then give me good results on both bands…?

Maybe I will install a battery pack in the same box.

The box with board installed:

The box completed front side:

Mind you,  it still needs some additional switches for the CW part of the transceiver.

73
Frank (ON6UU)

Video


Brilliant, Frank! I really appreciate the video as well–sounds like the kit produces smooth audio and should serve you well. No doubt, that military box enclosure will survive even the roughest field conditions!

Click here to check out the DB4020 kit at EA3GCY’s store.

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Proper Radio Prepping: Keep a kit that is always ready to hit the field!

My Red Oxx Micro Manager packed with a full radio field kit

Yesterday, my family packed a picnic lunch and took a drive through Madison County, North Carolina. It was an impromptu trip. Weather was forecast to be pretty miserable that afternoon, but we took the risk because we all wanted to get out of the house for a bit.

Although that morning I had no intention of performing a Parks On The Air (POTA) activation, my family was supportive of fitting in a little radio-activity, so I jumped on the opportunity!

A quick glance at the POTA map and I determined that the Sandy Mush State Game Land (K-6949) was on our travel route. Better yet, the timing worked out to be ideal for a lunch picnic and before most of the rain would move into the area.

Ready for radio adventure

I had no time to prepare, but that didn’t matter because I always have a radio kit packed, fully-charged, and ready for the field.

My Red Oxx Micro Manager EDC pack (mine is an early version without pleated side pockets) holds an Elecraft KX2 field and antenna kit with room to spare (see photo at top of page).

The Micro Manager pack easily accommodates the entire kit

This 20 year old blue stuff sack is dedicated to antenna-hanging. It holds a reel of fishing line and a weight that I use to hang my end-fed antenna in a tree or on my Jackite telescoping fiberglass pole. The sack also accommodates a 10′ coax cable.

The Elecraft KX2 transceiver, EFT Trail-Friendly Antenna, hand mic, CW paddles, C.Crane earphones, and wide variety of connectors and cables all fit in this padded Lowe Pro pack:

The advantage to having a simple, organized radio kit at the ready is that everything inside has its own dedicated space, so there’s no digging or hunting for items when I’m ready to set up and get on the air.

This level of organization also makes it easy to visually inspect the kit–missing items stand out.

Yesterday I parked our car at one of the Sandy Mush Game Land parking areas, deployed my field antenna, and was on the air in a matter of seven minutes at the most.

Hunter Parking Area Sign

Technically, this should read “Activator” parking area! (A questionable inside joke for POTA folks!)

We planned for heavy rain showers, so I fed the antenna line through the back of my car so that I could operate from the passenger seat up front.

I also brought my Heil Proset – K2 Boom Headset which not only produces better transmitted audio than the KX2 hand mic, but it frees up my hands to log stations with ease. This is especially important when operating in the front seat of a car!

The great thing about the KX2 is that it’s so compact, it can sit on my clipboard as I operate the radio (although typically I have an elastic strap securing it better). Since all of the KX2 controls are top-mounted, it makes operation a breeze even in winter weather while wearing gloves.

Since I routinely use the KX2 for shortwave radio broadcast listening as well, I know I always have a radio “locked and loaded” and ready to hit the air. My 40/20/10 meter band end-fed antenna works well for the broadcast bands, as long as there is no strong local radio interference (RFI). When I’m faced with noisy conditions, I pack a mag loop antenna as well.

What’s in your radio go-kit?

Having a radio kit stocked and ready to go on a moment’s notice gives me a great sense of security, and not just for recreational ham and shortwave radio listening reasons.

Sometimes I travel in remote areas by car where I’m more than an hour away from the nearest town and where there is no mobile phone coverage.

If my car breaks down, I know I can always deploy my radio kit and get help from the ham radio community in a pinch. Herein lies the power of HF radio!

If you haven’t built a radio go-kit, I’d highly recommend doing so. Although I’m a bit of a pack geek, keep in mind that you don’t need to purchase special packs or bags for the job. Use what you already have first.

I’m plotting a detailed post about the anatomy of an HF radio field kit. In the meantime, I’m very curious how many of you in the SWLing Post community also have a radio kit at the ready–one based on a transceiver or receiver.  Please comment!

Better yet, feel free to send me details and photos about your kit and I’ll share them here on the Post!


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Snagging two state game lands in three days for Parks On The Air

View from Waterrock Knob on the Blue Ridge Parkway (June 13, 2020).

You might have noticed from recent posts, I’ve been on a bit of a POTA (Parks On The Air) kick lately.

I’ve been enjoying taking the Xiegu G90 to the field and seeing just how well it performs under intensive use on battery power. So far, it has certainly proven itself to be a capable field rig.

Still, on two recent activations I also brought my trusty Elecraft KX2 along as well.  Without a doubt, it’s still my number one field rig. It will be difficult for another field transceiver to displace it.

With that said, the G90 is less than half the price of the KX2 (when the KX2 is configured with the optional ATU). The G90 can also pump out a full 20 watts of power–nearly double that of the KX2. I also love the G90’s spectrum display which makes it so easy to find free frequencies and hunt other parks. Its internal antenna tuner–like the KX2’s–can match almost anything very quickly.

Here are a couple of quick reports from my recent activations:

William H Silver State Game Land (K-6967)

Saturday, my family had planned a trip to visit my father-in-law. My wife encouraged me to find a nearby park to activate as there are so many between our house and his. I made it slightly more challenging by deciding to find a park or POTA entity I’d never visited.

Turns out the William H Silver State Game Land was only a 30 minute detour. I had never visited it and, in fact, it was even an ATNO (All Time New One) for Parks On The Air, meaning no one had yet activated it.

I had initially planned 1.5 to 2 hours for the activation, but we were running behind Saturday morning so I had to cut my time at the park to a total of about one hour–which included set-up, operation, and take-down.

We arrived at the site and I immediately deployed my EFT Trail-Friendly end-fed antenna.

My 12 year old daughter (who is studying for her ham radio license and is a great at digging callsigns out of the noise) helped me log contacts. I stuck with very brief exchanges so that I could work as many stations as possible. When activating an ATNO, I always want to give as many POTA “hunters” as possible the best opportunity to put the site in their log books.

I started on the 40 meter band and worked 20 stations in 25 minutes with the Xiegu G90.

I then moved up to the 20 meter band and switched over to the Elecraft KX2.

Turns out, 20 meters was pretty unstable, so I worked very few stations. I did work a station in California with 10 watts and a wire, though, so I’ll still call that a success.

I plan to visit this same site again later this year–it’s very accessible.

Buffalo Cove State Game Land (K-6886)

Monday morning, even though the weather outlook was dodgy, I scheduled another park activation which, like Saturday’s, was at a state game land which was another ATNO.

I like game lands. Unlike state parks, I don’t have to worry about crowds and I also usually get to take my Subaru or truck off-road. Access roads here in the mountains are typically steep, curvy, and washed-out in places. Finding the site can be very challenging, too. Still, I love adding a little off-road fun to a park activation!

The Buffalo Cove State Game Land is much larger than park K-6967 (above). I drove deep into the lands and found a large parking and camping area for hunters. I had the whole place to myself, so I found the best tree to support my end-fed antenna.

I operated the KX2 exclusively on this activation because I wanted to use its voice keyer and my Heil headset for hands-free VOX operation.

In the course of 90 minutes, I worked 51 stations from the trunk/boot of my car.

Many thanks to my good friend Mike (K8RAT) who made the whole process much smoother by spotting me on the POTA site.

Band conditions were actually pretty rough today, so I was very pleased with the results and intend to return here for a weekend activation later this year as well. This would actually be an ideal location for making low-noise portable SDR recordings while camping overnight.

This weekend, I decided I want to increase my portable field antenna arsenal. More about that in a future post!


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Help building a general coverage QRP transceiver list

Over the past few weeks, I have been building curated lists of ham radio transceivers. It all started when I needed to learn about multimode VHF/UHF transceivers for my EME project. As I got deeper into the process, I decided to make my master list of VHF/UHF multimode transceivers public. The goal with the list was to familiarize myself with the makes/model numbers and have an easy way to check out any used gear deals.

Next, I started a list of QRP general coverage transceivers–something I had been meaning to do for ages because I get so many inquiries about these from readers.

To be clear, by “general coverage” I mean radios that can receive HF and possibly MW broadcast bands in addition to ham radio bands. By “QRP” I mean radios that have output power of about 20 watts or less–some define the term QRP more strictly, but since our list has less to do with the transmitting function, I’m a little more flexible.

I like QRP general coverage transceivers because they’re often portable, have modest power requirements, and some offer superb sensitivity and selectivity for broadcast listening.

Click here to view the list so far.

Please comment if you note a missing transceiver. I’m certain I’ve left some out. I’d appreciate model numbers and links if possible. If you’ve ever owned one, please consider sharing your thoughts on its performance from the point of view of an SWL as well.

I’ve already started working on a list including all general coverage transceivers. It’s massive so it could be a while before it’s published! I’ll certainly ask for your input then as well.

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Taking the Xiegu G90 on an impromptu Parks On The Air (POTA) activation

Yesterday, I was in my hometown helping my parents with a few projects. Around noon, I realized that I had a good four hour window of free time–a true rarity these days!

I had two fully-packed go bags in the car: one with my trusty Elecraft KX2, and one with my recently acquired Xiegu G90.  On the heels of a successful POTA activation this weekend, I was itching to activate a new POTA site.

I did a quick check of the POTA site map and decided a trip to the South Mountains State Park (K-2753) was in order. The park was a nice 30 minute drive on back roads, so why not?

I posted a quick announcement on the POTA website, and jumped in the car.

When I arrived at the park, I noted an excellent, easily accessible picnic site with a nearby tree to hang my EFT Trail-Friendly antenna. Since I hadn’t been to this park in many years, I continued driving to check out other potential POTA sites.

In the main parking lot, I spotted a ham radio operator’s car with a prominent callsign on the back window and a POTA bumper sticker. I couldn’t see their operating site from the parking lot and since we’re all trying to social distance these days, I didn’t bother searching for them to introduce myself.

While it’s certainly allowed to have two activators running a park at the same time, I really didn’t want to impose and certainly didn’t want to cause any QRM by operating on the same meter band.

Contingency plan

I had a “Plan B” in mind in case the park wasn’t accessible.  On the west side of South Mountains State Park there was another POTA site: the South Mountains State Game Land (K-6952). I started driving in that direction, then used Google Maps to help me locate the entry road. Turns out, it was an additional 35 minutes of driving! Still, it was a beautiful day so no complaints from me.

The road was typical of game land roads: gravel and washed out in places. I had to ford one creek. My Subaru had no problem doing this, of course. (I actually love off-roading, so secretly I hoped the road would be more challenging!)

About four miles in, I found a pull-off that was big enough for my car and had an ideal tree to hang the antenna. I backed into the site, opened the hatch on the Subaru, and used the trunk/boot as my radio table.

Within ten minutes I had the G90 on the air.

I started calling CQ on the 40 meter band and thanks to buddies Mike (K8RAT) and Vlado (N3CZ) I was spotted on the POTA website.

Although there was a fair amount of QRN on 40 meters, now that the G90 has an RF Gain control (with latest firmware v 1.74), I could easily mitigate it.

I worked a number of stations on 40, then decided to move up to 20 meters.

I was very impressed with the response on 20 meters as well. Fading (QSB) was very deep, however, so I kept contacts brief. At times, stations would call me, I’d give them a 59 report, and when they’d reply I could barely hear them (and vise-versa). It took a little patience and good timing, but I believe I worked everyone who called me.

In the end, I had a total of 27 contact in the log with about one hour of operating. Here are my log sheets:

After transmitting steadily for an hour at a full 20 watts, the G90 body was pretty warm to the touch, but it had operated flawlessly.

A great field radio

The G90 is a gem of a transceiver and has some features that make it ideal for field use.

For one thing, I love being able to keep track of my battery voltage on the display:

Also, the G90 has excellent selectivity. On both 40 and 20 meters, at times I could see adjacent stations on the spectrum display that would have bled over and created QRM on less robust receivers.

I also like the ability to control all of the major transceiver functions without  having to dive into an embedded menu. Adjusting the filter, RF gain, attenuator, and pre-amp, for example, is super easy.

I love the spectrum display, too. In the field, it’s nice to be able to find an open frequency by simply watching the display for a minute or so before calling QRL or CQ. It also allows me to see when folks are tuning up nearby to make contact with me.

Although I’ve been using a resonant antenna in the field, the G90 has a very capable built-in ATU.  Back home, I’ve used it and have been very impressed with its ability to find good matches. Yesterday, for fun, I was even able to get it to tune up the EFT Trail Friendly antenna on 80 meters! I doubt it would be efficient, but the ATU did find a 2:1 match.

The only two features I feel like the G90 is missing are a notch filter (both manual and auto) and a voice keyer. I’m sure a notch filter could be added in a future firmware update (others have been asking for this as well), but I doubt a voice keyer could be added as easily. In truth, the voice keyer is a bit of a luxury, but it’s a feature I use without fail on my KX2 since park and summit activations often require constant CQ calls. Being able to record a CQ and have the radio automatically send it allows the op to drink water, eat lunch, and relax between contacts.

This is a lot of radio for $450 US shipped. I’ve also learned that the G90 has a very active community of users via this Groups.io email list.

I had planned to sell the Xiegu G90 after my upcoming review in The Spectrum Monitor. I must admit: this transceiver is growing on me. It might be hard to let go of it.


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Taking the Xiegu G90 QRP transceiver to the field!

Earlier this week, I took delivery of a new Xiegu G90 general coverage QRP transceiver. I’m reviewing this portable rig for The Spectrum Monitor magazine. Although this Chinese manufacturer has been around for a few years, this was my first purchase of a Xiegu product.

I’ve had the G90 on the air from home for a couple days, but I feel like the best way to test a QRP transceiver is in the field!

Due to the Covid-19 lock-down and a number of our regional parks either being closed or severely limiting visitors, I haven’t made many POTA (Parks On The Air) activations this year.

Recently, however, North Carolina has been opening state parks and allowing visitor access to hiking trails and picnic areas, but keeping all facilities (stores, cafes, visitor centers, and restrooms) closed to the public.

Yesterday, our family decided to pack a picnic lunch and head to Mt. Mitchell State Park (POTA site K-2747). My wife knew I was chomping at the bit to play radio in the field and actually made the suggestion. (She’s a keeper!) 🙂

There were only a dozen people at the park so we essentially had the place to ourselves. Better yet, it gave me the opportunity to pick out the most ideal picnic site to set up and deploy my EFT Trail-Friendly 40/20/10 antenna.

The G90’s backlit color display was actually quite easy to read in the field. My phone’s camera filter made it look darker than it actually was.

My POTA activation was unannounced and I didn’t have Internet access to self-spot on the POTA website, so I started the activation old school by calling “CQ POTA” until someone happened upon 7286 kHz.

After perhaps 10 minutes of calling CQ, Greg (KE0HTG)–a helpful POTA chaser–finally found me and spotted me on the network.

I worked a few stations in succession, but summer QRN levels were incredibly high and I believed static crashes were cloaking would-be contacts. The G90 has no RF Gain [Actually, thanks to this feedback, I now know the G90 does indeed have an RF Gain control (firmware version 1.73 and higher).] I asked one kind operator if he would hold while I switched over to my trusty Elecraft KX2.

The KX2 did a much better job managing the noise and that same op was easily readable where with the G90 I could barely copy him. I suspect I could have tinkered with the G90’s AGC levels to better mitigate the noise, but I didn’t want to do this in the middle of an activation.

I worked about fifteen stations with the Elecraft KX2 on 40 meters.

One real advantage of the KX2 during a POTA activation on SSB is its voice memory keyer (of course, it also has a CW memory keyer). I simply record my CQ and have the KX2 repeat it until someone replies, then I hit the PTT to stop the recording. Not only does this save my voice, but it also gives me an opportunity to eat my lunch while calling CQ!

I eventually moved up to the 20 meter band and switched back to the Xiegu G90.

On the 20 meter band, the G90 handled conditions like a champ.

Someone eventually spotted me on 20 and I worked a few stations.

The 20 meter band was very fickle and unstable yesterday. For example, I struggled to finish a contact with an operator in Massachusetts, yet got a solid 59 report from Spain with only 20 watts.

No activation is complete without brewing a cup of coffee on the alcohol burner!

I had a great time with the G90 in the field. I can see why it’s become such a popular transceiver as it offers incredible bang-for-buck (it can be purchased new as low as $450 US shipped).

This week, the noise levels on the 40 meter band should be very high here in North America, so I plan to spend more time with the G90 settings and see if I can mitigate the QRN a little better. I’d welcome any tips from G90 owners.

And yes, I’m already eyeing a couple of parks to activate next week!

Post Readers: Please comment if you’re familiar with the Xiegu G90 or any of the other Xiegu transceivers.


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The Yaesu FT-70G: Where the FT line met Milcom

Earlier today, I stumbled upon a very unique transceiver in Universal Radio archives: the Yaesu FT-70G.

Here’s the description from Universal:

The Yaesu FT-70G is a portable HF transceiver covering 2 to 30 MHz transmit. Receive is from 500 kHz to 30 MHz. Frequency selection is via BCD switches to 100 Hz. There is a clarifier for fine tuning. Optional FNB-70 NiCad Battery. Please note that the optional 10F-2.4DL filter is required for LSB opeation.

The Yaesu FT-70F is similar, but is a channelized fixed version offering up to 11 frequencies.

Two hours ago, I was not aware that the FT-70G existed.  Now? I want one!

I’m a real sucker for vintage rugged field radio gear, so I never discovered the FT-70G until today. Turns out, they’re relatively rare. A little light research reveals that it’s a highly-desired transceiver in the world of HF Packers–those radio enthusiast who like “manpack” commercial and military gear.

The FT-70G has a distinct military look and feel with the BCD switches to change frequency, rugged toggle switches, chassis extensions to protect the front panel, and attached screw-on connector caps.

What’s really surprising is that the FT-70G has a general coverage receiver (500 kHz to 30 MHz). Admittedly, it would not be fun band-scanning with those BCD switches…but still!

This website has a number of photos. They also have a product description likely from the original Yaesu/Vertex Standard FT-70G description:

“The FT-70 series HF field portable manpack transceivers are designed to provide reliable communications under rugged conditions in the military and commercial environment. The frequency synthesized, all solid-state circuitry and die-cast anodized aluminum enclosure and battery pack make a highly portable, weatherproof station. Flexible operation for optimum communications under a wide range of propagation conditions are assured by SSB (USB, LSB), semi break-in CW, AM, or audio interfaced Data modes. All controls, antenna, and interface ports are available and selectable via the front panel for maximum effectiveness and ergonomics in field, base, and manpack applications. The companion antenna tuner FC-70 is compatible with walking manpack, field portable, or base configurations. The highly effective vertical tripod mount antenna system YA-70 is deployed and stowed easily and quickly, pulling double duty by converting to manpack whip while on manuevers. High quality handset YH-70 provides communications privacy and clarity.”

Again, check out the excellent photos of the full manpack kit.

As I researched pricing, I discovered this FT-70R with accompanying FC-70M antenna tuner on eBay right now with only 6 hours left of bidding:

At time of posting, the bids are at $520. I fear this will soar well above my comfort level before bidding ends. (Like I need another field radio anyway, right?)

Post readers: Please comment if you’re familiar with the FT-70G and especially if you’ve ever owned one.  I’d love to hear about your experience with this unique rig.

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